Effect of maternal nutrition on embryo survival, uterine environment and embryo transfer in sheep

BRUNO- GALARRAGA, M.M.; ALVAREZ L.; DE LA SOTA, R.L.; CRISTINA C.; BONADEO N.; GIBBONS, A.; FERNÁNDEZ J.; CUETO, M.; LACAU-MENGIDO, I.M.

Foz do Iguazu

Simposio; 10th International Ruminant Reproduction Symposium; 2018

Colegio Basileiro Reproduction Animal

Maternal nutrition is an important factor that influences the processes of implantation and embryonic development. The objective of this study was to evaluate the effect of nutritional status of donor and recipient ewes on embryo survival and uterine gene expression. The study was carried out in the Laboratory of Small Ruminants Reproduction of INTA Bariloche during the breeding season. Merino donor (n = 36) and recipient (n = 75) ewes were randomly assigned to two treatment diets, receiving 1.5 (Supplemented, [S]) or 0.5 (Restricted, [R]) times daily maintenance requirements during 21 days before recovery and transfer of embryos. Estrus synchronization was performed with intravaginal sponges (Progespon®) for 14 days and an i.m administration of eCG (Novormon®) at time of sponge removal. Donor ewes received a superovulatory treatment, which consisted of the administration of 100 mg of FSHp (Folltropin V®, Bioniche, Canada) in 6 decreasing doses every 12 hours. Intrauterine artificial insemination with frozen semen (100 million spermatozoa) was performed 12 hours after estrus detection. On day 7 post estrus, embryos were recovered and evaluated from S and R donors and were transferred by semi-laparoscopy procedure to S and R recipients, defining the following groups: SS, SR, RS and RR. Embryo survival rate was determined by ultrasonography on day 22 post embryo transfer. At embryo recovery, biopsies were obtained from the uterus of donors (n = 26) and recipients (n = 10) and stored in liquid N2until analysis. The embryo survival rate was analyzed using the CATMOD procedure of SAS. Two way ANOVA, followed by post-hoc Tuckey tests, was performed to compare relative mRNA expressions. Data are presented as least square means ± pooled standard errors. Means were considered different when p ≤ 0.05, and with a tendency to differ when p < 0.1. The uterine gene expression of the receptors for progesterone (PR), insulin growth factor 1 (IGF-1R) and leptin (LEPR) was determined by real-time PCR. At time of embryo transfer, R donors (0.14 ± 0.06) and R recipients (0.08 ± 0.03) had lower uterine relative mRNA levels for PR compared with S donors (0.39 ± 0.15) and S recipients (0.86 ± 0.0) (P